خيارات البحث
النتائج 4311 - 4320 من 7,292
Cadmium phytoremediation potential of Deenanath grass (Pennisetum pedicellatum) and the assessment of bacterial communities in the rhizospheric soil النص الكامل
2022
Kumar, Pankaj | Fulekar, Madhusudan Hiraman
Phytoremediation technology is gaining excessive consideration as a promising method for heavy metal remediation from contaminated soil. In the present research study, a greenhouse trial was performed to assess the proficiency of Pennisetum pedicellatum as a potential plant species for the remediation of cadmium from the soil. Four sets of treatments i.e., (Tₒ) control, (T₁) 25 ppm, (T₂) 50 ppm, and (T₃) 100 ppm were studied till 60 days. Soil and plant samples were collected at a regular interval of 15 days after the seed sowing and analysed for different physicochemical properties and Cd concentrations from each treatment. The cadmium uptake was studied in the roots and shoots independently to examine the cadmium accumulation in P. pedicellatum. The present study showed that P. pedicellatum accumulated cadmium mostly in their roots compared to the shoots resulting in the accumulation of Cd from the soil. The finding indicates that P. pedicellatum is a virtuous plant species to restore cadmium-contaminated soil. It effectively banished 83% of Cd from the 100 ppm spiked soil at the end of 60 days. The microbial characterization of rhizospheric soil was also done using serial dilution and spread plate procedures to determine the presence of bacterial species in the rhizospheric soil. Seven bacterial strains were isolated from the soil and were further assessed for their biochemical, molecular, and phylogenic characteristics. The 16S rRNA sequencing analysis confirmed the presence of different bacterial species such as Alcaligenes sp., Bacillus drentensis, Bacillus subtilis, Bacillus foraminis, Bacillus wudalianchiensis, Bacillus amyloliquefaciens, and Planococcus ruber. This study concluded that phytoremediation using P. pedicellatum is a fascinating and compelling green technology for the remediation of cadmium from soil.
اظهر المزيد [+] اقل [-]Removal of Arsenate from Aqueous Solution by Synthetic Siderite-Modified Biochar: Characteristics and Mechanisms النص الكامل
2022
Yu, Wenting | Guo, Huaming | Hou, Chaoshuo
High arsenic groundwater has been observed throughout the world, which poses severe health impacts on human beings. It urgently needs effective adsorbents to lower arsenic concentration from the target groundwater for the purpose of drinking. In this study, siderite-modified biochar (SID-BC) was synthesized with the hydrothermal method as an adsorbent for arsenate (As(V)) removal from aqueous solution. Batch experiments were performed to investigate the effects of the mass ratio of siderite to biochar (i.e., 4:1, 4:2, 4:3, and 4:4), contact time, initial As(V) concentration, temperature, and solution pH on As(V) adsorption on the adsorbents. The highest adsorption of As(V) was observed on the SID-BC with the mass ratio of 4/3 (SID-BC-4–3), which may result from the high specific area of the adsorbent (8 times larger than the pristine biochar and 4 times larger than the pristine siderite). Adsorption kinetics revealed that As(V) adsorption was in line with the pseudo-second-order model. As(V) adsorption on SID-BC-4–3 was better fitted to Langmuir isotherm and D-R model, relative to Freundlich isotherm, with the maximum calculated adsorption capacity of 33.6 mg g⁻¹. Thermodynamic study showed that the adsorption reaction was an exothermic nature and a spontaneous process. Although Cl⁻ and SO₄²⁻ showed negligible effects on As(V) adsorption, HCO₃⁻, CO₃²⁻, and PO₄³⁻ had an evidently negative effect on the adsorption of As(V). The lowest As(V) adsorption was observed with the coexistence of PO₄³⁻. Results of SEM, XRD, FTIR, and XPS indicated that the adsorption was controlled by the chemical process via the complexation of As(V) with Fe–O and co-precipitation with Fe(III) hydroxide.
اظهر المزيد [+] اقل [-]Investigation on the application of by-product steam in iron ore sintering: performance and function mechanism النص الكامل
2022
Wu, Yufeng | Fan, Xiaohui | Ji, Zhiyun | Gan, Min | Zhou, Haoyu | Li, Haorui | Chen, Xuling | Zhao, Yuanjie | Zhang, Rongchang | Lai, Ruisi
The combustion-supporting effect of steam to coke breeze in sintering has the potential to improve sinter quality and reduce pollutants emissions. The results show that increasing the by-product steam injection concentration (0.32–0.47vol%) and prolonging the injection time (5 min) within a proper range (10–15 min) can improve sinter quality. 2.13kgce/t₋ₛᵢₙₜₑᵣ of the fuel consumption was decreased by reducing coke breeze usage from 5.60 to 5.45% under the recommended parameters, with 15.16% decrease of CO in sintering waste gas. By comparing experimental data with thermodynamic calculations, although the reaction between CO and steam can reduce CO emission and generate H₂, steam tends to react with coke breeze to generate H₂ and CO (react at 674℃), and OH radical produced by H₂ which can reduce the activation energy of CO oxidation reaction is the key to reducing pollutant emissions. The potential economic benefit of steam injection technology was calculated based on a 360m² sintering machine (the annual sinter output is 3.2million tons), excluding the equipment modification and steam injection cost of $300,000; a profit of $737491.2 per year or 0.23 dollars per ton sinter can be achieved. Therefore, low-carbon and cleaner iron ore sintering production can be realized through applying by-product steam.
اظهر المزيد [+] اقل [-]Spatial and dynamic effects of air pollution on under-five children’s lower respiratory infections: an evidence from China 2006 to 2017 النص الكامل
2022
Chen, Yi | Yang, Yining | Yao, Yongna | Wang, Xuehao | Xu, Zhongwen
Air pollution has been a deeply concerned issue posing an immediate and profound threat to human’s lower respiratory health in China. The health of children under 5 years old, regarded as a key index of public health progress in a country, is closely related to the long-term human capital development. Hence, it is vital to investigate the potential association between air pollution and children’s lower respiratory health outcomes and to explore related policy implications regarding the public health and the pollution regulation. As air pollutants diffuse across adjacent regions rather easily, considering the spatial spillover effect is meaningful in course of acquiring the aforementioned association. Based on the proposed province-level panel dataset of China during 2006–2017, this study constructs a dynamic spatial panel Durbin model to investigate the impact of air pollution on under-five children’s lower respiratory infections. As a result, (1) both air pollution and children’s respiratory health have obvious spatial spillover effects, and the latter has an outstanding characteristic of path dependence in time. (2) In the short term, air pollution presents significant negative impact on children’s respiratory health, while in the long run, the impact decreases dramatically. (3) Regional comparison indicates that children in the western China are the most susceptible to air pollution followed by children in the central and eastern regions. (4) Other control variables have significant and varying impacts both in the short and long term. Particularly, this paper proves the existence of “siphon effect” in children healthcare system in China. From a broader and more comprehensive perspective, this study provides effective and constructive basis for policy making, in favor of improving children’s health under air pollution and promoting sustainable development in China.
اظهر المزيد [+] اقل [-]Analysis of factors affecting industrial symbiosis collaboration النص الكامل
2022
Sonel, Edanur | Gür, Şeyda | Eren, Tamer
The rapidly increasing population causes an increase in consumption amounts day by day. This leads to negative effects such as the reduction of limited resources. In order to eliminate or reduce such negative effects, sustainable approaches are adopted for the future. Industrial symbiosis is one of these sustainable approaches. Industrial symbiosis is when two or more economic enterprises operating independently of each other form beneficial partnerships. In this study, the factors affecting industrial symbiosis collaboration were determined by literature review and by analyzing these factors; it is aimed to eliminate inefficiencies and to ensure the sustainability of established relations. The criteria determined are weighted with the Analytical Network Process method, which is one of the multi-criteria decision-making methods, and it is aimed to calculate the degree of importance and priority.
اظهر المزيد [+] اقل [-]Promising effects of parasite-derived compounds on tumor regression: a systematic review of in vitro and in vivo studies النص الكامل
2022
Aṣgharī, ʻAlī | Nourmohammadi, Hassan | Majidiani, Hamidreza | Shariatzadeh, Seyyed Ali | Anvari, Davood | Shamsinia, Sadegh | Ghasemi, Ezatollah | Shams, Morteza | Basati, Gholam
The parasites are repeatedly confronting their host to take advantage of nutrients for multiplication and survival. In this sense, a wide spectrum of molecules is released from both sides, with immune-regulatory activity, accompanying this biological battle. Such parasites and their valuable molecules can be directed toward microbial-based cancer therapy. Herein, we contrived a systematic review to gather information on the antitumor activity of parasite-derived compounds. Following systematic search in Web of Science, ScienceDirect, Scopus, PubMed, ProQuest and Embase until 31 December 2019, a total number of 51 articles (54 datasets) were finally included in this review. Thirteen parasitic agents were found to possess possible antitumor activity, comprising protozoan species Toxoplasma gondii, Trypanosoma cruzi, Trichomonas vaginalis, Acanthamoeba castellanii, Besnoitia jellisoni, Leishmania major, Plasmodium yoelii, and Plasmodium lophurae, as well as parasitic helminths Toxocara canis, Echinococcus granulosus, Taenia crassiceps, Trichinella spiralis, and Schistosoma mansoni. Most experiments were done based on antigenic preparations from T. gondii (16 studies), E. granulosus (10 studies), T. spiralis (8 studies), and T. cruzi (6 studies). Possible antitumor properties of the selected parasites were revealed in this review. However, precise molecular basis of anticancer activity for each parasite remains to be elucidated in the future.
اظهر المزيد [+] اقل [-]The nexus between environmental regulation and ecological footprint in OECD countries: empirical evidence using panel quantile regression النص الكامل
2022
Chu, Lan Khanh | Tran, Tung Huy
Environmental regulation is an important tool for policymakers to achieve environmental goals. To better understand the role of environmental regulation in protecting the ecosystem, this paper offers a new perspective on exploring the heterogeneous impact of environmental policy stringency on the ecological footprint in 27 OECD countries during the period 1990–2015. An advanced economic method, panel quantile regression, is conducted to deal with the non-normality and unobserved individual heterogeneity across countries. The estimation outcomes indicate that the environmental effect of policy stringency is heterogeneous along the quantiles and different between the ecological footprint of consumption and production. The beneficial role of environmental regulation in reducing consumption ecological footprint is achieved at quantiles under 80th but the harmful effect starts occurring at extreme high quantiles. In contrast, environmental policy stringency plays a consistently useful role in mitigating production ecological footprint. In addition, the results disclose that the effects of other driving factors such as international trade, energy efficiency, renewable energy, and income are heterogeneous at different quantiles of ecological footprint. These findings help explain the inconsistencies in previous empirical studies on the nexus between environmental regulation and environmental quality in OECD countries. Finally, the current study gives policymakers useful recommendations on how to strengthen the beneficial impacts of environmental policies on the ecosystem.
اظهر المزيد [+] اقل [-]The influence of finance on China’s green development: an empirical study based on quantile regression with province-level panel data النص الكامل
2022
Xu, Guangyue | Chang, Huiying | Yang, Hualiu | Schwarz, Peter
Finance has a strong role in promoting green development; however, there are very few studies quantifying this relationship. To this end, based on the official green development indicator system of the Chinese government and province-level data from 2006 to 2017, the quantile regression model was used to analyze quantitatively the impact of finance on green development. The results show that financial development contributed significantly to green development, and furthermore, financial efficiency and green finance have a strong positive effect with the increase of the quantile, and financial scale also has a significant positive effect, but a diminishing marginal effect. In addition, the impact of financial development on green development has regional differences. In the eastern region, the finance factors can promote green development, but the financial scale and the green finance promotion function weaken along with the quantile increase. The financial scale and green finance do not support green development significantly in the central region. Financial scale, efficiency, and green finance support green development in the west region.
اظهر المزيد [+] اقل [-]Oxidation of Textile Dye Through Electrocoagulation Process Using Scrap Iron Electrodes النص الكامل
2022
De Maman, Rafaela | Behling, Laura | da Luz, Vilson Conrado | Dervanoski, Adriana | Rosa, Clarissa Dalla | Pasquali, Gean Delise Leal
The textile industry stands out as one of the largest consumers of water among the industrial sectors. Additionally, its effluent presents characteristics such as high load of chemical oxygen demand (COD), total organic carbon (TOC), suspended solids, color, turbidity, phenol, and salts, which require an efficient treatment of the wastewater produced. Among the several researches that have arisen focused on the treatment of textile effluents, electrocoagulation stands out. This method consists of an electrochemical process that generates its own coagulant by applying electric current to metal electrodes immersed in the solution. The electrodes used in the present study are metallic plates made of scrap iron. The objective of this work is to evaluate their application in an electrocoagulation process for the decolorization of real and synthetic effluents. The efficiency of the treatment was evaluated by applying it to a synthetic effluent containing commercial indigo blue dye and to a real effluent from the textile industry, assessing parameters such as color, turbidity, pH, electrical conductivity, COD, TOC, phenol, soluble iron, sludge generation, and electrode wear. The synthetic effluent obtained average color removal of 95%, 96% phenol, and low sludge production in 120 min of electrolysis. In the real effluent from the textile industry, an average color removal of 92%, 97% turbidity, 100% phenol, 65% TOC, and 49% COD in 90 min of electrolysis was obtained. The electrocoagulation process using scrap iron as electrodes proved to be efficient in removing the dye present in the real textile industry effluent, as well as in the synthetic effluent.
اظهر المزيد [+] اقل [-]The relationship between short-term PM2.5 exposure and outpatient visits for acne vulgaris in Chongqing, China: a time-series study النص الكامل
2022
Li, Xiang | Zhou, Lai-Xin | Yang, Li-Li | Huang, Xiao-Long | Wang, Nan | Hu, Yue-Gu | Tang, En-Jie | Xiao, Hua | Zhou, Yu-Meng | Li, Ya-Fei | Lu, Yuan-Gang | Cai, Tong-Jian
Many researches have reported the air pollution impacts, either long term or short term, on inflammatory skin diseases, but there are few studies on the relation between PM₂.₅ and acne vulgaris. To determine the correlation between short-term PM₂.₅ exposure and acne outpatient visits, data for 120,842 acne vulgaris outpatient visits between December 2013 and December 2019 were obtained from three large hospitals in Chongqing, China. Both single-pollutant models and two-pollutant models were established to explore the relationship between PM₂.₅ exposure and acne outpatient visits. The stratified analyses were conducted through two-sample z-tests to investigate the possible gender (male or female) and age (< 25 years or ≥ 25 years) differences in PM₂.₅ effects. The results demonstrated positive correlations between PM₂.₅ concentrations and acne outpatient visits. A 10 μg/m³ increase in PM₂.₅ concentration was associated with a 1.71% (95% CI: 1.06–2.36%) increase in acne outpatient visits at lag 0–7 day. Stratified analyses showed that PM₂.₅ effects were greater in individuals aged ≥ 25 years than those aged < 25 years, but no gender difference was found. In conclusion, short-term PM₂.₅ exposure was positively associated with the risk of acne outpatient visits, especially for people ≥ 25 years old.
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